Now, however, the mottled soaps, blue and grey, are produced by working colouring matter, ultramarine for blue, and manganese dioxide for grey, into the soap in the frame, and mottling is very far from being a certificate of excellence of quality.
It has been suggested that ultramarine is a compound of a sodium aluminium silicate and sodium sulphide.
Mixed with Ultramarine gives a range of soft mauves.
The new coloring used a rich ultramarine blue, rich yellow and a subtle green after the style of traditional Dutch tin-glazed ware.
The design of the former is a trellis crossing the ceiling diagonally; in each of the lacunae is carved a cherubim with eight wings; the figures and the trellis are gilded; the ground is a rich ultramarine.